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  <title>Document</title>
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<body>

  <div id="app">

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  <script>

    var cities = ['beijing', 'tianjing', 'shanghai']
    var rs = ['<ul>'];
    cities.forEach((item, index) => {
      rs.push(`<li>${item}</li>`)
    })
    rs.push('</ul>')
    $("#app").append(rs.join(""))
  </script>



</body>

</html>